In factories it is common for workers to push or pull carts for various reasons, such as to deliver parts and subassemblies between assembly stations or assembly lines. In the past, such carts were not specifically developed or manufactured for specific load ratings. Moreover, the loading of such carts was not controlled. Due to these two conditions, it is common for workers to overload the carts, or to select a cart that is not suitable for the loading condition. Therefore, workers commonly have difficulty moving the carts, resulting in reduced manufacturing efficiency and possibly injury to the worker.
Accordingly, there is a need in the art for a method and device to determine the forces required to move a cart. There also exists a need in the art for a method to determine an appropriate cart design based upon the expected loading and use of the cart.
Therefore, the present invention is directed toward a method and device to determine the forces required to move a cart. The present invention is further directed toward a method for determining an appropriate cart based upon the expected use of the cart.
In accordance with one aspect of the invention, a device for measuring forces exerted on a movable element includes a force generating and applying device, a load cell, and a controller. The force generating and applying device is selectively actuatable to move in a first direction and the force generating and applying device is operatively connected to the movable element so as to cause said movable element to move in the first direction. The load cell is connected to the force generating and applying device and is operable to sense the force exerted upon the movable element. The load cell transmits data corresponding to the sensed force to the controller. The controller receives the transmitted data and displays the transmitted data in a predetermined format.
In further accordance with the present invention, a device for measuring forces exerted on a cart to move the cart in a first direction is provided. The cart has a first end and a second end, a pair of casters being disposed under each of the first and second cart ends. The cart first end is adapted for engagement with a load member for application of forces to the cart. The device includes the load member, a force generating device, a load cell, and a controller. The load member has a proximal end and a distal end, the distal end being operatively engaged with the cart first end while the proximal end is operatively engaged with a force generating device. The force generating device is operable to move the load member in a first direction toward the cart and in a second direction away from the cart.
In accordance with a method of the present invention, the load member operatively engages the first end of the cart and the force generating device is actuated to move the load member in a first direction and thereby applies forces and moves the cart in the first direction. The load cell measures forces applied to the cart by the load member, and transmits measured forces to a controller. The controller displays the measured forces in a predetermined format.
In further accordance with the present invention, a method for identifying a preferred cart for a desired application from a plurality of possible carts, includes the steps of determining a maximum load for the desired application, accessing a database wherein each cart of the plurality of possible carts is correlated with a maximum force required to move the cart under the maximum load, and, selecting a cart from the plurality of carts by identifying the cart corresponding to the smallest maximum force under the maximum load. The selected cart is the preferred cart for the desired application.